1. What is Hull Speed?

Hull speed is the speed at which the wavelength of a vessel's bow wave equals the waterline length, creating increased drag. It represents the theoretical maximum efficient speed for displacement hulls.

2. How Does the Calculator Work?

The calculator uses the hull speed formula:

Where:

• 1.34 — Empirical coefficient for displacement hulls
• Waterline Length — Length of boat at waterline in feet

Explanation: The formula calculates the speed (in knots) at which a displacement hull creates a wave system that efficiently supports the boat.

3. Importance of Hull Speed Calculation

Details: Knowing hull speed helps in boat design, fuel efficiency planning, and understanding performance limitations of displacement hulls.

4. Using the Calculator

Tips: Enter waterline length in feet. The value must be greater than 0. The result shows theoretical hull speed in knots.

5. Frequently Asked Questions (FAQ)

Q1: Can boats exceed hull speed?
A: Displacement hulls can exceed it with sufficient power but become very inefficient. Planing hulls can exceed it by rising over their bow wave.

Q2: Does hull speed apply to all boats?
A: No, it mainly applies to displacement hulls. Planing hulls and semi-displacement hulls can exceed this speed.

Q3: Why is the coefficient 1.34?
A: This empirical value accounts for typical wave-making resistance characteristics of displacement hulls in salt water.

Q4: How does waterline length affect speed?
A: Longer waterline length allows higher hull speed because the wave system can be longer before becoming inefficient.

Q5: What factors aren't considered in this calculation?
A: Hull shape, displacement, power, sea conditions, and fouling can all affect actual speed capabilities.